Hurricane Isaac could offer some drought relief and enough moisture to powder-dry soils to germinate and grow emergency fall grains such as oats, rye or wheat in the southeast and as far north as Missouri.
The key will be for farmers in the path of these rains to plant in the next day or two so that seed is in the ground prior to the rain, say University of Missouri dairy and forage specialists. The specialists held an hour-long conference call this noon to discuss drought management strategies.
The specialists also offered a warning: Significant rainfall can increase nitrate content in corn, with the highest levels found three to seven days after the rain. Rob Kallenbach, Missouri Extension forage specialist, recommends not harvesting corn silage for at least a week following a significant rainfall event to allow nitrate levels to drop.
As an emergency forage crop, oats offers perhaps the most fall tonnage, with as much as 2 tons/acre. In Missouri, however, oats will not over-winter. Annual ryegrass or cereal rye will produce as much as 3,000 lb. for forage this fall, overwinter and offer another two tons next spring. Wheat will produce 1,500 to 2,000 lb. of forage this fall and one to three tons next spring, says Kallenbach.
Kallenbach recommends planting the emergency grain crops in row-crop fields that have already been harvested, such as corn or soybeans taken for silage. “Tall fescue will come back with rain, and will out-compete fall seeded grains,” he says.
Farmers should also be concerned about herbicide carryover from the previous crop. Farmers may want to do their own bio-assays by collecting soil from the top ½” from several locations in the field into a pot and then planting the intended grain into that soil. If you keep it well watered, you’ll know within five days whether there is herbicide carryover, says Kallenbach.
Tony Rickard, a Missouri Extension dairy nutritionist, also highly recommends producers test all locally grown forages for nitrates. Missouri labs are finding elevated levels of nitrates, even in high-chopped corn silage. Plus, he recommends a full nutrient analysis on all forages simply so you’ll know energy and fiber levels of the feed and how best to utilize them in the ration.
For the urricane rain predictor, click here.
For answers to more drought questions, click here.
And for herbicide restrictions for haying, grazing and silage, click here.